SCIENCE and INVENTIONS.

New Zealand Herald, Volume LIX, Issue 18019, 18 February 1922, Page 3 (Supplement)

SCIENCE and INVENTIONS.

FROGS IN STONES.

There ha s been a good deal of excitement at a Werneth Low quarry in the Marple district of Chester, where somo men broko up a huge stone, out of which leaped several frogs. All over the neighbourhood ran the news that these frogs had been imprisoned in tho stone since it was mado millions of years ago. No frog can live in a stone for a million years, or a thousand years, or a hundred years, or a hundred months, or a hundred weeks, unless it has some means of obtaining food from outside. It may bo only a crevice through which moisture and insects can creep, but often such a supply has kept frogs alivo a long time. Tho truth about this case must bo that the frogs had crept into the stone through some crevice the workmen did not notico before thoy broke it up. Perhaps they might have crept into the stone when they were quite small and, growing too big to escape, remained imprisoned until tho stono was broken. Tho idea that frogs have lived in stones for ages is not true.

BATTLESHIP TARGETS. The up-to-date " battle-practice target" used by the United States Navy is mounted on a boat-shaped raft 170 feet long very substantially built. Along the middle of the raft's deck, from stem to stern, runs a series of holes in which a scries of fifty or more masts of small diameter and twenty-five feet high-one

might call them poles—are stepped. Across these masts is nailed a latticework of thin planks to make a vertical plane. This rectangular piano is the targot. When it is wanted for gun-practice uso, tho raft is towed, so as tu offer a moving object to shoot at. The target is supposed to represent an enemy ship, and in actual battle, of course, tho ship aimed at would bo moving at considerable speed. In practice with guns tho projectiles are painted freshly, a different colour for each gun, <and thus there is no disputing which hole in tho target has been made by gun-pointer Jones or gunpointer Smitli. The paint which stains the edges of the aperturo proves tho case. Battle practice targets of the type hero described are made of different sizes for guns of different calibres. Thus for sixinch guns the object screen is smaller and a shorter raft is used. When firing is done at short ranges it is customary to employ a canvas screen instead of a lattice target. The United States Atlantic Fleet is doing its annual gun praetico in Cuban waters, and for this purpose tho supply ship Lebanon started from Norfolk for Guantanamo recently with 16,000 pieces of target material on her decks and stowed in her hold. These included a number of large box-kites, meant to represent aeroplanes, for anti-aircraft guns to attack. A new typo of target, of canvas, is a silhouette representing a submarine.

INCENDIARY BOMBS. c The aeroplane has Jsnt a fresh horror j to warfare by rendering it practicable to set fire to enemy property over unlimited areas beyond the fighting front. " Inccn- J diaries" (as they are called) suitable for ( this purpose had not been developed to any great extent up to the- outbreak of f the late war, but during that gigantic ( conflict they were multiplied and made incomparably more efficient. Even now, in all countries, the Warfare Sovvico is working hard at the problem, in the expectation that in the- uext war such agents of destruction will bo employed much more extensively. Early in the recent war phosphorus naturally suggested itself las an incendiary agent. To put it out is ; almost'impossible, and a small pellet of it falling upon a man will inflict painful burns that take weeks to heal. Hence the common use of phosphorus bombs. A solution of yellow phosphorus in carbon bisulphide will take fire of its own accord on exposure to air. Tho mixture finally decided upon as bast by the United States Chemical Warfare Service, for use in "drop bombs," consists of these two ingredients together with benzine heavy oils, and a small quantity of TNT. This compound was tested by hanging a can of it from a support, and firing riflo bullct.s through tho can. A stream then issued without ignition until tho liquid reached this ground, when it took fire as it spread. Thrown upon water, it spreads rapidly, and burns fiercely, but for this sort of use, to ensure ignition, small chunks of sodium (which is set on firo by contact with water) are added. A mixture of lubricating oil with 25 per cent, of ammonia nitrate gives, when discharged from bombs, immense flames which burn for ten or twelve- minutes. This compound; used together with " thermit," proved tho most effective "incendiary" during tho war. Thermit has familiar industrial useV. It is composed of aluminium and iron rust, both finely powdered and thoroughly mixed together. When raised 1 to high temperature by the setting oft ol a small charge of high explosive, the 1 oxygen in the iron rust rushes over to i the aluminium particles (for winch it has greater chemical affinity) with such ylo. I lence as to convert the whole mass into i a flaming fluid. The newest " intensive , tvpe" bomb is loaded with thermit, supplemented by sodium nitrate and a i solid oil. The thermit liquifies fte oil, so that by the time the container is burned through and melted, there is a tremendous ! burst of flume. Most of the bombs , dropped bv the Germans in England car- ; ried thermit. The British "baby, incendiary bomb" extensively used during the war, was loaded with the same destruc- ' tivo mixture, to which barium nitrate was added.' These babies weighed only ' six and a half ounces ajiece and were ' packed in a tinned iron container, which, according to size, held from 144 to 270 of 1 them One Handley-Page bombing airplane could carry 16.000. They could be • dropped in the container, to fly m al l directions when explosion followed impact with the ground.